EP 0 240 747 A1 describes a lever actuated roll-up shade for motor vehicles. The roll-up shade is to be used for reducing solar radiation through the rear window in order to prevent the interior from heating up quickly. In addition, the extended roll-up shade reduces the demands on the air-conditioner when there is strong solar radiation.
The known roll-up shade has a wind-up shaft mounted so that it can rotate in a roll-up shade housing. Two two-armed levers spaced apart along the wind-up shaft are hinged to the housing. The rotational axis of the levers lies perpendicular to the longitudinal axis of the wind-up shaft. Sliding blocks, which slide in a guide groove of the pull rod, are disposed on the free end of the longer of the two arms. The roll-up shade web has one edge attached to the pull rod, with the other edge of the roll-up shade web being anchored to the wind-up shaft.
For moving the roll-up shade web and keeping it in tension, a spring motor is provided in the interior of the wind-up shaft. For extending the roll-up shade web against the effect of the spring motor, a gear motor is provided to which crank levers are attached that are connected via rods to a short arm of each of the two-armed levers.
If the gear motor is operated in the appropriate rotational direction, the two-armed levers are moved from the rest position, in which they lie approximately parallel to the wind-up shaft, into an erected position. In this way, they tension the roll-up shade web and also carry the pull rod during the tensioning movement. For support, two holding grooves, in which the pull rod travels, is located at the top end of the rear window so that vibrations in connection with the elasticity of the two-armed levers do not permit the pull rod to contact the window.
For retracting the roll-up shade, the gear motor is set in gear. It remains in gear for a predetermined time, which is greater than the longest expected retraction time. Measures that slow the lever movement when they approach the rest position or the retracted position of the roll-up shade are not provided. The impact when the pull rod or the levers strike the housing accordingly can be hard.
It is further known to respectively use two toggle-lever arrangements, instead of the two-armed levers, each of which is hinged with its free ends on one side of the housing of the wind-up shaft and on the other side to the pull rod. The axes of these hinges and also the knee joint which connects the knee-lever arms to each other, are parallel to each other and perpendicular to the wind-up shaft. Again, no control is used to slow the movement speed of the knee-lever arrangements when the pull rod approaches the retracted end position that is defined by mechanical stops.